Sharpening device for edged tools



Sept. 4, 1934. c. E. BEARDSLEY 1,972,126

SHARPENING DEVICE FOR EDGED TOOLS Filed Oct. 26, 1932 INVENTOR BY ZyM Patented Sept. 4, 1934 UNITED STATES 1,972,126 SHARPENING DEVICE FOR EDGED TOOLS Charles E. Beardsley, Bethlehem, Conn, assignor to Scovill Manufacturing Company, Waterbury, Cnn., a corporation of Connecticut Application October 26,

8 Claims.

This invention relates to an improved sharpening device for edged tools, and is particularly adapted for use in the sharpening of safety razor blades, preferably of the thin, double-edged type.

It is an object of the invention to provide a device in which the blade to be sharpened may be very readily inserted and removed, and in which the blade may be quickly conditioned either by sharpening it in a manner equivalent to stropping or in a manner equivalent to honing, at the election of the user.

In the accompanying drawing illustrating a preferred and a modified form of the invention,-

Figure l is a perspective View of a sharpening device embodying the invention, the parts being indicated as having been opened to facilitate the insertion or removal of a blade.

Fig. 2 is a perspective view of the same device, the parts being indicated as having been closed, in readiness to effect a sharpening operation.

Fig. 3 is a cross-sectional view through the sharpening device illustrated in Figs. 1 and 2 and an inserted blade.

Figs. 4 and 5 are perspective views respectively of the blade-holder and abrasive element or sharpening tool of a device embodying the invention in modified form.

Fig. 6 is a longitudinal, cross-sectional view, and Fig. 7 is a transverse sectional view, of the modified sharpening device illustrated in Figs. 4 and 5.

It is commonly known that a properly conditioned cutting edge of a razor or similar sharpedged tool, when highly magnified, presents an appearance somewhat resembling that of a saw. In other words, the edge instead of being smooth consists of a-series of teeth of microscopic dimensions. After the edged tool or razor blade has been used to accomplish its intended purpose it becomes dull and has to be sharpened or otherwise reconditioned for service. If the dulled edge of a razor blade is examined with a microscope it is found that the elements corresponding to saw teeth have been turned or bent out of their original positions, thus destroying their effectiveness. The dulled edge may, as is well known, be reconditioned by a sharpening of the character known as stropping, which tends to restore the minute teeth to their original positions, or, if necessary, the deformed teeth may be worn away and a new edge produced by a sharpening of the character generally known as honing.

It is the purpose of the present invention to provide a simple device by which a razor blade or other sharp-edged tool may be readily recon- 1932, Serial No. 639,537

ditioned either by a sharpening corresponding to stropping or a sharpening corresponding to honing, without the necessity of making any change in the parts of the mechanism.

In the preferred form of the inventionillustrated in Figs. 1, 2 and 3 of the accompanying drawing, the sharpening devicecomprises a bladeholder 20 and an abrasive device or other appropriate sharpening tool 21 between which a razor blade 22, indicated in broken lines in Fig. 1 and in full lines in Fig. 3, may be inserted. The holder 20 should provide means whereby the edged tool to be sharpened may have its edge-or edges properly positioned for sharpening engagementwith the surface of the abrasive element. The portion'of theabrasive element which makes contact with an edge of the tool should be inclined at an appropriate, acute sharpening angle. The abrasive element should be held in frictional contact with the surface of the tool bordering upon an edge to be sharpened. The degree of frictional engagement should be capable of being varied in accordance with the character of sharpening to be effected, and, as an important feature of the invention, the abrasive o element should be movable to a limited extent in the holder in a direction crosswise but not necessarily at right angles with respect to the edge of the tool.

In the preferred form of sharpener herein se- 35 lected for purposes of illustration, which is adapted for the sharpening of a double-edged safety razor blade, the holder comprises a sheet of metal having a base portion 23 and upwardly-turned end flanges 24. A pair of ribs 25 may be pressed 9 upwardly from the base portion of the holder to provide suitable supports or blade rests to serve as a backing means for the razor blade, and, as a means of holding the blade in a well-defined position in the holder, a pair of upwardly-extending blade-positioning elements 27 may be so disposed as to enter the openings commonly provided in commercial blades when the blade is properly positioned on the supports. These positioning elements 2'7 may, if desired, have attaching portions passed through auxiliary surface portions 28 pressed upwardly from the bottom of the holder and riveted at the under side as at 29.

The abrasive element 21 should have portions of its under surface which lie along the edges of the razor b1ade inclined outwardly and downwardly in opposite directions as indicated at 30. These surfaces may, if desired, be slightly curved so as to conform. with an arc of a circle as indicated in Fig.3, although, if properly inclined at a sharpening angle, the curvature is not essential.

In order that the height of the blade-positioning elements 2'7 need not be unduly limited, the abrasive element may be provided with a central,

longitudinally-extending, grooved portion 31 to aiiord ample clearance at the top of the positioning elements.

The abrasive element may be thickened to provide the mass or weight of material required to maintain its sharpening surfaces in frictional contact with thesurface of the blade to be sharpened and under a pressure sufiicient to effect a sharpening corresponding with a stropping of the blade without the application of any additional pressure. If desired, this additional abrasive material relied upon to increase the mass of the abrasive element may be applied in the form of upwardly-extending ridges or ribs 32 defining depressed portions 33, the ribs and depressions being adapted to serve as finger-holds when it is desired to apply additional pressure to the' abrasive element during a sharpening operation corresponding to honing. In the absence of the ribs 32 and depressions 33 the parts of the holder may be roughened as indicated in Figs. 4 to 7, or

either part may be provided with any other appropriate means to afford a suitable hold for the thumb or finger.

The abrasive element may be made of a length which is shorter than the distance between the 'fianges 24 only to an extent such as to provide a satisfactory working clearance, in which case the flanges serve as means to prevent relative endwise movement between the abrasive element and the holder and as guides to confine the move- 'ment of the abrasive element to its intended crosswise or lateral movement.

As a means of limiting the lateral movement of the abrasive element with respect to the holder, the former may be provided with headed pins 34 in engagement with slots 35 near the ends of the flanges 24. These slots 35 should be of slightly greater width than the pins, as indicated in Fig. 3, in order to provide for the circular movement of the pins in the slots as the abrasive element 'moves over the edges of the razor blade.

By using one pair of pin-and-slot connections between the abrasive element at one end only of each of the flanges 24, these pin-and-slot connections cooperate to form a satisfactory hingelike joint between the abrasive element and the holder, as best indicated in Fig. 1.

'It has been found as a result of experience that the sharpening of an edge is best effected if the edge ismoved over the abrasive surface in a direction which is neither lengthwise nor exactly perpendicular to the edge, but in a direction which has a component parallel with the edge and another component perpendicular to the edge. This most desirable direction of movement between the blade and the abrasive element may be taken advantage of in practicing the foregoing invention by disposing the longitudinal axis of the blade-positioning elements 27, the blade-supporting ribs 25 and the blade-sharpening surface portions3ll of the abrasive element at an angle of inclination with respect to the direction of movement of the abrasive element in the holder, as clearly indicated in Fig. 1. When so positioned, the blade will be held at, a slight angle of inclination with respect to the direction of movement of the abrasive element and the holding ribs 25 will be disposed just within and parallel to the edges of the blade, thereby causing the edge to be held with uniform pressure against the overlying surfaces of the abrasive element.

The base portion 23 of the holding device will preferably be extended slightly beyond the sides of the abrasive element, as indicated at 36, 37, so that the holder may conveniently be held between the thumb and fingers of the hand, as indicated in Fig. 2, and, when so held, the stropping movement of the abrasive element may be satisfactorily effected by imparting a slight lateral shaking or vibratory movement to the holder. When so vibrated the abrasive element will be alternately thrown from its center position, indicated in full lines in Fig. 3, to the broken-line positions indicated respectively at the right and left ends of Fig. 3. The direction of movement is indicated by the double-headed arrow. The manner of using the sharpening device should be obvious. The blade to be sharpened is inserted when the abrasive element has been opened to the position indicated in Fig. 1, the abrasive element is then closed to the position indicated in Fig. 2, and, if a mere reconditioning of the edges of the blade corresponding with a stropping operation only is to be effected, the

thumb and finger of the hand, the frictional contact between the abrasive element and the blade being produced by the force of gravity due to the added mass of abrasive material used for such purpose. If a honing, rather than a stropping, of the blade is to be effected, the holder may be held in one hand while the abrasive element is moved back and forth over the razor blade by the fingers of the other hand, the ribs 32 and depressions 33 affording a satisfactory fingerhold for such purpose. The degree of pressure applied by the fingers should be carefully adjusted to the sharpening pressure which it is desired to apply to the blades.

If desired, the honing operation may be effected by grasping the parts of the holder between the thumb and fingers of one hand.

After a sharpening operation of the razor blade with one surface uppermost, the holder maybe opened, the positi' n of the blade reversed, the holder closed, and a sharpening operation effected either as to strapping or honing with the other side uppermost.

It will usually be found that a blade may be kept in satisfactory condition for several successive uses as a result of what has been referred to as a stropping operation only between each use, after which what has been referred to as a honing operation will prepare it for another series of uses if conditioned by strapping only.

Although, in the preferred form of the invention thus far described, the abrasive element has i been indicated as being positioned above the blade-holder and the relative movement of the two parts of the sharpener has been indicated as being disposed in a direction crosswise with respect to the length of the blade to be sharpened, neither of these conditions is at all essential.

Either ofthe two elements of the sharpener may blade-holder 20 and an abrasive element 21',

inverted and vibrated between which may be interposed a razor blade 22 to be sharpened, the blade beingindicated in broken lines in Figs. 4 and Sand in full lines in Figs. 6 and '7. r

The. blade-holder difiers from the corresponding element of the sharpener illustrated in Figs. 1 to 3, inclusive, in that the flanges 24 have been omitted, and the blade-positioningribs 25' and the longitudinal axis of the blade-positioning elements 2'7 are parallel with the edges of the holder. The body portion 23' of the holder is intended to be heavier than the holder of the preferred form, and the blade-positioning elements 2'7 are intended to be somewhat longer, for reasons which will hereinafter be explained.

The abrasive element 21' also differs from the corresponding element of the preferred form ofsharpener in that the longitudinal axis of its inclined sharpening surfaces is parallel with its edges, and a pair of openings31', preferably of circular form, are substituted for the channel 31 of the corresponding element of the preferred form of sharpener.

The sharpener illustrated in Figs. 4 to 7, inclusive, may be used with either element uppermost.

As clearly indicated in Figs. 6and '7, the abrasive element is somewhat longer than the bladeholder, and the blade-holder. is somewhat wider than the abrasive element. By thus making one of the elements of greater length than the other, the longer element may be readily held between the thumband fingers of the hand of the operator during a sharpening operation when the holder is being held with that element under the other. On the other hand, by making one of the elements wider than the other, the wider element may be readily held between the thumb and fingers of the hand of the operator during a sharpening operation when the wider element is lowermost. It is, of course, of no consequence which of the two elements is made longer and which made wider than the complementary element.

when the sharpening device is used with the blade-holder uppermost, the blade-holder should be of a weight such that the force of gravity alone will cause the blade to be hrid in contact with the abrasive element with a sufiiclent degree of pressure to effect a satisfactory stropping of its edges when the parts are vibrated; If desired, the blade-holder and abrasive element may be of relatively different weights, in which case the device may be vibrated first with the heavier element uppermost to produce a preliminary stropping operation, after which the device may be with the lighter element uppermost to produce a more delicate finishing operation. These operations may, of course, be effected firstwith one side of the blade directed towards the abrasive element and then with the other side directed towards the abrasive element.

The blade may be inserted in the sharpening device either by placing it upon the blade-holder when positioned with the blade-locating elements 27 extending upwardly, then applying the abrasive element so that'the elements 27' will extend into the openings 31', and afterwards inverting the sharpener if it is desired to operate the device with the blade-holder uppermost; 'or the blade may be laid upon the abrasive element with its two end openings over the holes 31' and the blade-holder applied by causing the blade-locating elements 2'7 to enter the end openings in the blade.

It is, of course, obvious that the recesses 31'. need not necessarily extend all the way through the abrasive element 21'. All .that is essential is that the depth of the recesses and the length of the blade-locating elements 2'! be such as to satisfactorily limit relative 'movement between the two parts of the sharpening device in any direction in the plane of the blade.

As indicated in Figs. 5 and '1, the abrasive element should have surface portions so'inclined as to meet the surfaces of at appropriate, acute sharpening angles.

The outer surfaces of the abrasive elementand blade-holder may be knurled or otherwise roughened to provide finger-holds to facilitate the use of the device to effect a sharpening corresponding with a honing operation as distinguished from a strapping operation.

It will be apparent that the openings 31' in the abrasive element, and the blade-locating elements 27' of the blade-holder will cooperate as means to permit of a limited movement of one element of the sharpening device with respect to the other in a lengthwise direction, or in a transverse direction, or in any other direction substantially parallel with the plane of the blade; or, if desired, the two parts may be so vibrated as to the blade along its edges cause every portion of each-of the sharpening elements to have a circular movement with respect tothe other, the size of the circle being dependent upon the radii of the openings 31 and blade-locating elements 27'. It will also be apparent that the forms of the openings 31' need not necessarily be circular, and that the dimensions may be varied in accordance wth the char-' acter of relative movement desired.

The invention is not intended to be limited to either of the specific forms herein selected for purposes of illustration, but should be regarded as including modifications and variations thereof within the scope of the appended claims.

What is claimed is:

l. A sharpening device for a two-edged safety razor blade, comprising a holder and a sharpening tool between which may be interposed a blade to be sharpened, the tool having abrasive surfaces so positioned as to lie along the edge portions of the blade and inclined at acute sharpening angles with respect to its adjacent intervening surface, the holder having blade-backing means to make contact with the oppositesurface of the blade, and ing means being spaced inwardly from the edges of the blade so as to separate them from adjacent portions of the holder and provide clear spaces for the sharpening movements of the overhangthe margins'of the back ing portions of the tool, means for positioning the blade in a predetermined relation with respect to its backing means and for preventing material relative movement of the blade over the backing means in directions crosswise with respect to its longitudinal axis, and restraining means to limit movements of the tool over the blade in every part uppermost, is of sufficient weight to maintain a practically effective degree of sharpening friction between the tool and the blade as a result of the force of gravity alone, the movements of such uppermost part being unrestricted otherwise than by such force and the other movement- .restricting means herein specified.

2. A sharpening device for a safety razor blade, comprising a blade-holder having blade-supporting means and means for holding a blade in a definite, relatively fixed position while resting on the supporting means with its edge portions overhanging the same, an overlying abrasive element between which and the blade-supporting means a razor blade may be interposed, and means comprising movement-obstructing portions of the holder and the abrasive element to limit the movements of one with respect to the other in directions determined by the portions of the abrasive element in contact with the interposed blade, the under surface of the abrasive element including portions flared outwardly and downwardly along the zones adiacent the edges of an interposed blade at appropriate, acute bladesharpening angles, the abrasive element being held in frictional contact with the interposed blade by its own we'ght but being otherwise freely movable, to a material but limited extent, in opposite directions such as to have components which are crosswise with respect to the edges of theblade, the limitations of such movements being dependent upon the movement-obstructing portions of the abrasive element and holder.

3. A blade-sharpening device, as defined by claim 1, of which the holder comprises a metal plate having a pair of oppositely-disposed, upwardly-turned, spaced, parallel flanges between which the sharpening tool may be mounted, the dimension of the sharpening tool in a direction perpendicular to the flanges of the holder being less than the distance between the flanges only to an extent such as to provide a free working clearance.

4. A blade sharpener, as defined by claim 1, of which the blade-positioning means comprises a pair of upwardly-extending projecting elements so disposed in the holder as to coincide with and enter openings in a blade to be sharpened when properly positioned in the holder, and of which the blade-backing means comprise upwardlydisposed ribs so located as to lie within and parallel to the edges of the blade when the blade has been positioned by the said upwardly-extending projections.

5. A blade sharpener, as defined by claim 1 of which the means forlimitfng the blade-sharpening movement between the holder and the sharpening tool comprises pin-and-slot connections so positioned as to serve as a hinged joint about which the tool may be swung with respect to the holder to a position such as to facilitate the insertion or removal of a blade.

6. A blade sharpener, as defined by claim 1, of which the longitudinal axis of the blade-backing .means, the blade-positioning means, and the blade-engaging zones of the sharpening tool when in contact with an interposed blade is inclined with respect to the direction of movement 7 of the tool whereby the sharpening movement of the tool with respect to the surface of the blade will have both an endwise component and a crosswise component.

7. A blade-sharpening device comprising a holder and a sharpening tool between which may sharpened and so much of the tool as is relied upon 1 to sharpen the blade being of a suitably abrasive character, the holder having blade-backing means to make contact with the surface of the blade opposite that which faces the tool, and the portion of the, backing means along the edge to be sharpened being spaced inwardly from said edge so as to separate it from the adjacent portion of the holder and provide a clear space for the sharpening movement of, the overhanging porton of the tool, means for positioning and holding the blade in a predetermined relation with respect to its backing means including means for preventing material relative movement of the blade over the backing means in directions crosswise with respect to its longitudinal axis, and restraining means to limit movements of the tool over the blade in every direction including parts of the tool and holder so spaced as to permit material but definitely limited degrees of sharpening movement of one with respect to the other in directions having material crosswise components with respect to the longitudinal axis of the blade and of a combined reciprocating and rocking character determined by the. spaced zones of contact between the tool and the opposed structure, the tool and bolder comprising parts one at least of which, if the holder is held with that part uppermost, is of sufiicient weight to maintain a practically effective degree of sharpening friction between the tool and the blade as a result of the force of gravity alone, the movements of such uppermost part being unrestricted otherwise than by such force and the other movementrestricting means herein specified.

87 A sharpening device for a safety razor blade comprising abrasive portions having relatively inclined surfaces against which the edges of a blade may be held at appropriate sharpening angles, a blade-confining means in cooperative relation with the abrasive portions of the sharpening device by which the margins of a blade may be constantly pressed against the surfaces of the abrasive portions while free to be moved along said surfaces in other. directions, blade-positioning means comprising a pair of lugs so spaced and located with respect to the other parts of the sharpening device as to extend into a pair of openings in a blade when its margins are held in contact with the abrasive surfaces of the sharpening device, and means comprising stop elements and surrounding movement-obstructing elements each of a greater area than that of its enclosed stop elements for restricting the relative movements of said lugs with respect to the abrasive portions of the sharpening device, whereby the amplitude of movement of each lug and of every part of the blade engaged with the lugs may be so limited that each will be confined within but freely movable to any part of the area of an enclosure of given form and dimensions.

. CHARLES E. BEARDSLEY. 

